1. Field of the Invention
The present invention is directed toward an interactive method for sorting biological specimens using data processing techniques and, more particularly, toward an interactive method for use in combination with image analysis apparatus for sorting cervical smears by processing fields of view of an image analysis microscope and sorting out normal specimens and selecting potentially abnormal specimens, where a technician may review selected fields of view of potentially abnormal specimens.
2. Discussion of the Prior Art
Automated and semi-automated methods of examining Papanicolaou-stained cervical smears, commonly referred to as pap smears, have been proposed in several articles and have been the subject of patents and patent applications since the 1970's. Cervical smears are typically contained on microscope slides which, in current practice, are individually examined by a cytotechnologist. Of course, this is an expensive and time intensive practice which is prone to human error.
In an effort to automate the cervical smear analysis process, some methods propose automatically scanning cervical smears and saving images of scanned objects, such as cells. Saved images may be classified and later displayed to a cytotechnologist for review and diagnosis. Unfortunately, such approaches do not provide contextual information for the object and, as a result, may not provide information with sufficient specificity for discerning suspicious objects. The result may be more false positive identifications of cervical smear samples. False positive identifications of objects result in normal slides being presented to cytotechnologists for human review. Human review of false positive slides or objects may not be necessary in many cases, thereby tending to increase the cost of applying such proposed methods.
The performance requirement for a fully automated cytology system may be very high, especially, as regards sensitivity to abnormal slides. An automated cytology system will ideally sort normal slides from abnormal slides with a very low rate of classifying normal slides as abnormal. In setting sort criteria at a level sufficient to provide a useful normal slide sort rate, severe abnormal slides may be missed by fully automated systems. Reliable systems that match such high performance requirements with existing technology are desirable so that a useful, cost effective, automated cytology system may be developed.
In contrast to the prior art, the present invention provides a slide sorting strategy comprised of a combination of fully automated processing and interactive review components that meet high performance standards without sacrificing sensitivity for identifying abnormal slides. The method of the invention sorts slides into clearly normal, interactive review, and microscopy review categories. Slides classified as clearly normal may be reported without further processing. Slides classified as needing microscopy review may be further processed by human review under a microscope. Images in the interactive review category may be saved for slides. In contrast to the prior art, the present invention provides a cost effective means to sort slides by classifying only about 20% of slides as clearly normal. Thus, high sensitivity requirements for identifying abnormal slides may be met by the method of the present invention. The present invention also includes several improvements to the human review process for reducing human false positive slides and improving the normal slide sort rate after human review. These improvements further increase the cost effectiveness of the method of the invention.